Cholesterols exist in many cells and primarily play physiological roles of maintaining cellular functions as components of lipoproteins or biological membranes, serving as raw material for bile acid and various hormones, and the like. However, it is known that increased serum cholesterol levels resulting from excessive intake of foods with a high content of cholesterols lead to arteriosclerosis. In the modern dietary life with many opportunities of taking cholesterols, it is required to suppress the concentration of cholesterols in the body.
Furthermore, it has been reported that bacterial cells of Bifidobacterium bifidum, Bifidobacterium adolescentis, Bifidobacterium breve, Bifidobacterium infantis, and Bifidobacterium longum have blood lipid ameliorating effects (Patent Document 1). In particular, Bifidobacterium longum has been well studied, and reports have shown that Bifidobacterium longum SBT 2933R (FERM P-8743) has excellent effects (Non-patent Document 1), and use of cells of this bacterium or a culture thereof as a serum cholesterol elevation inhibitor has been proposed (Patent Document 2). In general, however, bacteria belonging to the genus Bifidobacterium are weak against oxygen as well as gastric acid and bile acid in the body. Therefore, there is a problem that, when cells of this bacterium or a culture thereof is orally taken, the cells have a poor survival ability in the gastrointestinal tract and show inadequate effects in many cases. Accordingly, bacteria belonging to the genus Bifidobacterium which have an excellent survival ability and a serum cholesterol elevation inhibiting effect have been desired.
However, it is only known about such bacteria belonging to the genus Bifidobacterium having an excellent survival ability that Bifidobacterium longum SBT 10254 (FERM P-14820) (Patent Document 3) and Bifidobacterium longum (FERM BP-7787) (Patent Document 4) have an excellent survival ability and show a serum cholesterol elevation inhibiting effect, that Bifidobacterium longum BB536, Bifidobacterium breve ATCC 15700, and Bifidobacterium animalis ATCC 25527 (Non-patent Document 2) show a cholesterol sedimentation effect, and the like. In the current situation, there are few options of microorganisms which have an excellent survival ability and a cholesterol inhibiting effect.
Furthermore, since it is often inevitable to store drugs or foods using these microorganisms for a long period, high storage stability is required. However, known microorganisms have a poor survival ability after long-term storage, and many of them have a poor survival ability, particularly, under a non-anaerobic condition.    [Patent Document 1] JP-A-61-271223    [Patent Document 2] JP-B-6-96537    [Patent Document 3] JP-B-3384907    [Patent Document 4] JP-A-2003-238423    [Non-patent Document 1] The 6th Japan Bifidus Foundation, Annual Meeting Proceedings, p. 18, 1987    [Non-patent Document 2] Letters in Applied Microbiology, Vol. 21, 149-151, 1995